The present invention relates generally to electric hair cutting devices, such as hair clippers and hair trimmers, and more specifically to blade sets for such devices. In particular, the present invention is related to blade sets designed for hair trimmers.
Conventional electric hair cutting devices include an electric motor having an output shaft with an offset cam engaging a blade set. The blade set includes a moving blade constructed and arranged to linearly reciprocate relative to a stationary blade. Both blades have complementary toothed edges, and the relative movement of the moving blade to the stationary blade creates a scissors-like cutting action. The blade set is usually removable from the device for cleaning, sharpening and other maintenance. A suitable example of conventional hair cutting device blade set design is disclosed in commonly-assigned U.S. Pat. No. 5,068,966, which is incorporated by reference. Hair clippers are usually considered more powerful and used for relatively larger cutting jobs, such as providing a major portion of a haircut, while hair trimmers are used for more detailed operations, such as trimming beards, mustaches and the like. As such, trimmer blade sets are often smaller in all dimensions than clipper blade sets.
One problem faced by trimmer blade set designers is maintaining the alignment of the moving blade relative to the stationary blade during the entire reciprocal path of cutting operation. Any misalignment of the moving blade can cause poor cutting or nicking of the person receiving the trim.
Another problem faced by trimmer blade set designers is providing the ability to move the position of the points or ends of the cutting teeth on the moving blade back and forth relative to the complementary teeth of the stationary blade in a direction transverse to the direction of blade cutting action, for the purposes of obtaining a cut closer to or farther from, the skin as desired. This feature is common on clipper blade sets, but it has been difficult to achieve in the smaller confines of a trimmer blade set.
Thus, there is a need for an improved hair trimmer blade set that addresses the design issues identified above.